This disclosure relates generally to flow switches for controlling fluid flow. More particularly, this disclosure relates to a flow switch having a pressure responsive member for controlling fluid flow.
This disclosure has application in conjunction with numerous fluid flow systems which employ a flow switch to generate an electrical signal to control the fluid flow through a conduit. One representative example to which the present disclosure relates is a flow switch of a type such as disclosed in U.S. Pat. No. 5,162,624. The flow switch employs a housing which can be molded from a polyvinyl chloride plastic material or other materials and which defines a flow path between an inlet and an outlet of the housing. The fluid flow system may be employed for various fluids. The housing has an extension which receives a bonnet assembly for mounting a flow switch. The switch assembly carries a magnetic field responsive signal generator such as a reed switch. Electrical leads extend through the body portion of the bonnet assembly. A displaceable shuttle is exposed to the fluid flow. The shuttle and the magnet are displaced by a calibrated flow rate so as to cause a signal generator to change state and transmit a signal from the leads. A bypass path which diverts flow from the main flow path may be opened to control the fluid flow.
The integrity of any flow switch and the ability of a flow switch to reliably function to control flow over a significant lifetime can be compromised when the flow switch is integrated into a flow passage which has a turbulent flow. An optimum regulatable flow is best realized with a long straight inlet conduit leading to the inlet for fluid exposure to the flow switch. However, space constraints for many installations do not allow for a sufficiently long straight flowpath.
The flow switch can also be compromised if the shuttle does not properly function concentrically or at a sufficiently precise aligned relationship to the flow path so that it slightly wobbles or engages against the metering orifice. The latter condition may be due to material creep over time or improper installation misalignment.
The orifice module of the present disclosure is capable of a dual function of reducing adverse consequences of turbulent flow such as may occur adjacent an elbow of a system and also providing a guide or holder for further ensuring that the flow switch assembly is properly concentrically aligned throughout its operation.